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Australian glaucoma study to have “far-reaching” impact

Progress has been made in the effort to predict a person’s risk of developing glaucoma, after Australian research discovered new genetic markers related to the disease.

A genome-wide study of more than 134,000 people undertaken by QIMR Berghofer Medical Research Institute, the Menzies Institute for Medical Research (MIMR), and Flinders University found 101 genetic markers that influence intraocular pressure. The lead author of the combined study, QIMR’s Associate Professor Stuart MacGregor, said the scientists were able to confirm for the first time that 40 of these markers also increased a person’s risk of glaucoma.

“The discovery of these previously unknown genetic markers for glaucoma will be important for improving our ability to test for and predict a person’s risk of the disease,” MacGregor said.

“Although a predictive test for glaucoma is not available yet, our discovery is very promising.”

According to the study, individuals with a large number of the genetic markers had an almost six-fold increased risk of developing glaucoma compared to someone who had fewer genetic variants.

Professor Jamie Craig, director of the Flinders Centre for Ophthalmology, Eye and Vision Research, said the findings had dramatically increased the current understanding of which genes caused glaucoma and high eye pressure.

“These previously unknown genetic markers for glaucoma will be important for improving our ability to test for and predict a person’s risk of the disease.”

Stuart MacGregor, QIMR

“We expect far-reaching consequences in terms of predicting who will develop glaucoma in the population, and exciting possibilities to develop better ways to treat this disease, which is a leading cause of blindness worldwide,” Craig said.

“We are getting much better at predicting these outcomes in patients and this will help us find people at risk and get them on sight-saving treatment early in the course of the disease.”

The latest findings increased the number of known genetic markers underpinning intraocular pressure by more than 90. According to MacGregor, the most surprising finding was the number of those variants that were associated with developing glaucoma.

“There is natural variation in eye pressure from person to person, and having high eye pressure doesn’t necessarily damage your vision. So for the 101 genetic markers we identified, although they are a risk factor, their presence in your genetic coding doesn’t necessarily mean you will develop glaucoma,” MacGregor said.

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“However, we were able to show 53 of the genetic markers do directly increase your risk of developing glaucoma and particularly increase the risk of developing advanced glaucoma, the type that tends to cause blindness.”

According to MIMR, the research was the largest genetic study of glaucoma ever undertaken and has its roots in the Glaucoma Inheritance Study in Tasmania (GIST), which was first established in the 1990s by Professor David Mackey.

Study co-author and MIMR researcher, Professor Alex Hewitt, said of the 101 genetic markers that influence intraocular pressure, 85 had not been known previously.

“This new work is important because we have identified a number of new genes that could be targeted as new therapies.”

Alex Hewitt, MIMR

“All the currently available treatments aim to reduce the pressure in the eye. This new work is important because we have identified a number of new genes that could be targeted as new therapies,” Hewitt said.

“Although a predictive test for glaucoma is not available yet, our new research will improve our ability to identify people at risk of developing glaucoma and this takes us one step closer to a preventative treatment that could stop people from going blind as they age.”